Assessing Site Suitability

General

Things to consider when selecting a site for an event:

• Available space
• Viewing space
• Traffic and pedestrian routes
• Ground conditions
• Position and proximity of noise sensitive buildings
• Geographical location
• Topography
• Location and availability of services.

Capacity

Calculations used are taken from The Guide to Safety at Sports Grounds (The Green Guide). Emergency exit calculations need to be included when determining crowd capacity. Remove the largest exit and include within the calculations. You also need to consider the space taken up by stalls and other infrastructure. There are two calculations to be made and once confirmed, use the lesser value of the two.

1. Area of event space / 0.5 (or the number of people per m²)
2. Calculations based on exit widths:
   • Total Exit Widths (m) (TEW) x Flow Rate (FR) x Exit Time (ET) = Capacity (C) (before including infrastructure and removing exits due to fire)

Flow Rates

The Guide to Safety at Sports Grounds (The Green Guide) indicates that the following number of people should be able to safely evacuate from an event space within one minute, per meter of different exit types. This also takes into consideration whether alcohol has been consumed, whether the exits are level, or whether steps are present.

• 82 people per minute through 1m of a level exit.
• 72 people per minute through 1m of a level exit, with alcohol consumption.
• 66 people per minute through 1m of a stepped exit. 66 is the upper limit.
• 56 people per minute through 1m of a stepped exit, with alcohol consumption.

Exit Times

The Guide to Safety at Sports Grounds (The Green Guide) indicates that the following amount of time that will be required to evacuate an area, depending on the level of risk and reason for evacuation:

• Low risk = 10 minutes
• Medium risk = 8 minutes
• High risk = 6 minutes

Example

As an example, an event space may have a Total Exit Width (TEW) of 20m over 5 exits; all exits are 4m wide. The exits are level and there has been no alcohol consumed, allowing for a Flow Rate of 82 people per minute. The reason for attendees leaving is that the event has ended, or a low risk, which allows for an exit time of 10 minutes. The calculation for this will look like: 20 x 82 x 10, giving you a maximum capacity of 16,400 people.

However, when the largest exit is removed, e.g. 4m, there are steps to navigate, alcohol has been consumed and there is a high risk event that requires the area to be evacuated, e.g. an emergency, the calculation becomes 16 x 56 x 6, giving a maximum capacity of 5376 people for the same event space.

Compare this total against the total of Area of event space, divided by 0.5 (or the number of people per m²), and the lower number is the maximum capacity.

Please Note: The capacity calculation formula is included for information only. This will need to be reviewed by the Safety Advisory Group (SAG) team for inclusion within the Event Safety Plan.